A. Field of the Invention
The invention relates generally to protection barriers and, more particularly, to durable, lightweight floating barriers that are used to protect areas such as harbors, water regions, or other types of land or water areas from high speed water craft attack.
B. Description of the Related Art
In the current environment with terrorist activities on the rise, there is a need to protect assets from terrorist attacks. One type of protection device is a floating harbor protection barrier system designed to provide protection to military and commercial harbors from high speech surface boat attacks.
Initial research into harbor protection by the Naval Facilities Engineering Service Center led to the development of a mostly-steel structure called the Port Security Barrier. The Port Security Barrier consists of three steel pontoons supporting a steel box beam, steel supports for netting, steel braces, and primary netting made up of 1.125 inch diameter nylon 12-plait line with a mesh size of one foot.
Another type of floating barrier device is described in the Naval Facilities Engineering Service Center Technical Report TR-2027-SHR, dated September, 1994 (hereinafter referred to as “Technical Report”). As described in the Technical Report, a lightweight floating barrier for defeating a high speed boat attack includes at least one 40-foot-long barrier module with a lightweight glass reinforced plastic (GRP) frame, low density closed cell foam floats, and a capture net woven from high strength Spectra™ line. Each barrier module can be folded for ease in transportation between locations, and assembly and installation of a lightweight floating barrier can be done with unskilled labor using simple tools and support craft.
While the use of GRP for components of a harbor protection barrier is an improvement over the use of a mostly-steel or an all-steel construction for a harbor protection barrier in some respects (e.g., lower maintenance costs), it still has problems associated with not being as structurally strong as the mostly-steel construction, and thereby it does not provide as good a protection or durability as one would get from the mostly-steel construction or all-steel construction of a harbor protection barrier. For example, a test described in the Technical Report (see FIG. 29 of the Technical Report) shows that a GRP protection barrier frame was shattered by a high-speed boat impacting the GRP protection barrier. One can surmise from that test that boats following a lead boat (which impacted the GRP protection barrier) may be able to follow the same path in the water as the lead boat and thereby penetrate into a region protected by one or more GRP protection barriers, which is clearly undesirable.
Furthermore, conventional GRP Port Security barrier modules are not particularly sturdy with respect to dealing with forces due to boat attacks and/or forces due to severe weather conditions.
Also, for an all-steel construction or for a mostly-steel construction of a Port Security barrier, there is a problem in that maintenance costs are very high. For example, when the Port Security barrier is floating in the water, it deteriorates over time due to the sea water that comes in contact with the steel. This leads to rusting, which causes deterioration of the Port Security barrier, thereby making it less structurally sound. While such steel-constructed Port Security barriers typically have a paint coat to partially counter the rusting problem, the conventional Port Security barriers have to be painted fairly often in order to maintain the structural integrity of the paint barrier, which again results in high maintenance costs.
Furthermore, with conventional Port Security barriers, there is a problem associated with coupling two or more harbor protection barrier modules together to protect a large region, such as a harbor. As described in the Technical Report, each protection barrier module is 40 feet long, and thus to protect a length of harbor of 150 feet would require four (4) protection barrier modules coupled together. The conventional method of coupling protection barrier modules to each other is via a loose coupling at the respective ends of adjacent protection barrier modules, typically by coupling a steel cable to respective ends of adjacent protection barrier modules. This loose coupling results in undesired stresses being imparted to individual protection barrier modules as they flop around in the water due to inclement weather conditions such as high wave and high wind conditions. Such a loose coupling between protection barrier modules may result in damage to individual protection barrier modules, with results in an undesired cost associated with repairing protection barrier modules already installed or having to utilize new protection barrier modules to replace protection barrier modules that are damaged beyond repair.
The present invention is directed to overcoming or at least reducing the effects of one or more of the problems set forth above, such as to provide a sturdy harbor protection barrier structure that can withstand hurricane force winds and that does not require much upkeep